Apparatus for molding ingots



y 1929. E. GATHMANN 1.719.542

' APPARATUS FOR MOLDING rueo'rs Filed March 10, 1928 2 Sheets-Sheet l WEI) 'ill'iia C) y 2, 1929- E. GATHMANN APPARATUS FOR MOLDING INGOTS Filed March 10, 1928 2 Sheets-Sheet 2 ll/l lllll'lllllllnllll Patented July 2 1929. t

UNIT-Ensures nun. earnmmw, or nam'monn, MARYLAND.

APPARATUS FOR MOLDING INGOTS.

Application filed.- latch 10, 1928. Serial No. 260,609.

This invention relates generally, to the art of casting metallic ingots and part cularly to apparatus for conserving. the heat contained in the molten mass in. its upper por 5 tion until the cooling and solidification of the in ot has rogressed from the bottom thereo upwar ly to its upper portion, thus assuring the complete solidification of the entire molten ingot mass w1thout the formation of an upper-air-chilled skin. While my present invention may be advantageously employed in the making of many kinds of ingots, it is best. adapted to the molding of slab ingots of the kind showman my U. Patent No.'1,616,039 of Feb. 28, 1928. The ingots may be cast and handledprior to treatmentin accordance with my invention in any suitable way. a

Any well known method may be employed in the casting of ingots in vertical molds but in the casting of ingots in horizontally arranged molds I prefer to employ the method and apparatusshown and descr bed 1n my co-pending application for patent Serial No. 214,584 filed Aug. 22, 1927 although my pres .ent invention is not limitedto the use of such method or apparatus. 1 t

Heat-insulating material, both refractory and combustible, has heretofore been appl ed to the upper portion ofingots in a molten or semi-molten state for the purpose of retarding solidification of this part ofthe ingot and thus provide liquid metal to compensate for the shrinkage in volume from thehquid to the solid state, thereby prevent ng the formation of pipe or shrinkage cavities, but this has always been done manually and in more or less of a haphazardmanner, the heat-insulating material beingusedbut once.

My present invention provides 1 forthe systematic and effective covering ofthe upper surface of the steel while liquidand for the a removal of theinsulating material g fterthe ingot has solidified but before it is lifted or dumpedfrom the mold. L i

I, preferably employ as a heat-insulating material a finely divided refractory substance, suc'has infusorial earth, powdered of ingot in the making of which my invenlime, or the like. While these substances are satisfactory non-conductors of heat, their use heretofore has been objectionable because of the inconvenience and dangers which they cause to the operatives due to the flotation in and the pollution of surroundin air durin the handling'of the ingots am? particular y during the removal of got.

the ingots from the molds. These objections to the use of such heat-insulating material for the purposes specified are entirely obviated by my invention which involves the emplo ment of. methods and apparatus where y finely divided heat-insulating material is maintained in a reservoir and deposited on the ingots without manual handling and is then after suitable intervals removed from the ingots and returned to the reservoir for reuse. The material is moved through a closed conveyor "and is at all times prevented, while passing from reservoir to ingots or from ingots to reservoir, from beclouding the atmospherein which the steel crew work.

More specificall the upper free face of the liquid which orms the ingot should be covered promptly after it has been teemed into the mold with the heat-insulating material, which is referablyof a refractory nature. and in a nely divided condition. This will cause the upper face ,of the ingot tobe maintained in a liquid or semi-liquidcondition until the remainder of the in ot has solidified. After the solidification o the ingotvinthis manner, the finely divided heatinsulating material is Withdrawn from the upper face of the ingot in such manner that it will not cloud. the surrounding atmosphere, and it is then deposited in or conveyed to a suitable receiver from which it can again be deposited on another liquid in- This cycle of operations may be repealted without substantial loss of the materia In this way not only is the steel completely protected butas the material is supplied to the ingots in definitely regulated quantities, the nature of the solidified ingot is materially improved.

My improvements are illustrated in the accompanying drawings which are largely diagrammatic.

Figure 1 shows a longitudinal section of an. apparatus designed for the hereinbefore mentioned.

Figure 2 is a perspective view of one type tion may be employed.

Figure 3 is a View partly ,in end elevation and partly in vertical section of the hopper or reservoir shown in Figure 1.

Fi re 4 shows a section on the line 4-4 of Figure 1. a a

The molds employed are preferably of the purposes kind shown in my U. S. Patent 1,661,039 of Feb. 28, 1928, although other types of molds ma be used.

is shown in the accompanymg drawings, each mold M consists of an iron box-like structure open at the top and having heavy bottom walls with side walls which gradually decrease in thickness from bottom to top. The bottom walls are cambered as indicated for purposes described 1n my atent above mentioned. The drawings s ow a series of molds mounted on or secured to a conveyor C which may be of any construction suitable for specific installations and practices.

The drawings show only a portlon of the conveyer but it will be understood that 11 is an endless conveyer and may be driven in any suitable way so as to carry the lngot containing molds beneath the apparatus which supplies and withdraws the heat-1nsulating material. The conveyor 1s moved forward step-by-step.

The apparatus shown consists of a closed hopper or reservoir A containing a finely divided or dust-like heat-insulating material B. This material may be maintained in a heated condition by electrically heated coils D or in other suitable ways. The hopper has a discharge spout E at the upper end of which is mounted a riddle or screen E which is adapted to reciprocate in a horizontal plane on guides f. The mesh of this screen should be such that when the screen is stationary, i. e., is not being vibrated, the refractory material, due to its natural packing tendency, will not pass through .the screen. The screen is adapted to be moved back. and forth by cams G which are so shaped and so operated as to give the screen a step-by-step or intermittent movement.

The cams may be mounted on shafts g which are operated in any suitable way as by gearing 9 (Fig. 1). Any other suitable mechanism for vibrating the screen may be employed.

A funnel-shaped receiver H is located above the conveyor 0 a suitable distance from the spout E and this receiver is connected by a pipe or conveyer J to a fan K driven by a motor L. The fan is connected with the upper portion of the hopper A. by a short pipe N provided with a valve 0 which may be used to control the passage of the material. from the conveyer to the hopper. The pipe N is providgd with an outlet branch pipe P equipped with a valve Q. This pipe P may be used in charging the hopper with the heat-insulating material or it may be employed as a by-pass for exhausting the ressure when material is not being conveye It will be understood that the depositing and the recovery of the heat-insulating material is an intermittent operation. The conveyor is moved intermittently or step-by step and the screen F is operated intermittently, the material being passed through the screen when a mold containing molten metal for forming the ingot is at rest below the spout E. When a mold with its ingot reaches the receiver H, the insulating material is withdrawn.

The amount of heat-insulating material in the hopper should at'all times be suflic'ient to cover a series of ingots though not necessarily a complete heat. No large additions to the hopper should normally be necessary as most of the material is recovered from the solidified ingots.

By depositing finely divided or commutated heat-insulating material, such as infusorial earth, powdered lime, or the like, on the forming ingots and retaining it there a suitable time, I maintain on the upper face of the ingot its approximate temperature as cast until cooling or solidification has progressed from its bottom to its upper face,

thus preventing the formation of doublev skins, shrinkage cavities, cold shuts or roughened surface zones and also lessening the oxidation of said surface during the cooling and solidification period. The interval of time between h application of heat-insulatingmaterial to tn..- ingot and its removal there om is governed primarily by the size (largely the depth) of the ingot being produced.

The ingots may be removed 1fr0m the molds by various methods now well-known to those skilled in the art.

The ingot I shown in Figure 2 has its bottom portion 13 inwardly cambered and its top portion 11' slightly depressed at its longitudinal axis. The depth of the ingot is considerably less than its width and the length is greater than said width. An ingot of this contour, the upper face of which has been kept liquid so that solidification occurs through progressive cooling from the bottom tothe top, is entirely free from pipe or shrinkage cavities as well as porosity if the molten metal has been suitably finished and degasified. Roughened patches snakes are entirely eliminated and there is very little if any oxide film so that the ingots are commercially usable in their entirety less the usual scale and end crop losses.

Due to the. relatively thin vertical section of an in 0t of this type, segregation of the metalloi s is veryslight as segregation is substantially proportional to the time of solidification and solidification is proportional to the least vertical dimension of the ingot.

Many modifications in the apparatus for applying and removing the heat-insulating material may obviously be employed without departing from the scope of my invention. 7

Not only are better ingots produced by my invention but, as before stated, the heat-insulating material may be used over and over and will not foulthe atmosphere.

1 claim as my invention:

1. An apparatus for producing sound ingots comprising a reservoir for heat-conserving, material, means for depositing material from said reservoir on the upper face oF ingot metal and means for retrieving said material from the'ingots for further use after the ingots have completely solidified. 2. An apparatus for producing sound ingots comprising a reservoir for heat-conserving material, means for heating said mate rial, means for depositing it. on the upper face of ingot metal and, means upon solidification of the ingot, for retrieving said material for further use.

terial from said reservoir 3. An apparatus for producing sound ingots comprising a reservoir for heat-com serving material, means for depositing material from said reservoir on the up or or free face of molten ingots, means or retricving said the ingots has been accomplished and means for returnin r it to the reservoir from which it was originally sup lied to the ingot.

4. An apparatus or producing sound ingots comprising a reservoir for heat conserving material, means for depositing maon the upper face of an ingot metal, and pneumatic means for retrieving said material from the ingots.

In testimony whereof, 'I have hereunto subscribed my name. a

EMIL GA H ANN;

material after solidification of 

